WO2014199621A1

WO2014199621A1 - Wireless communications system handover control method, relay device, and target cell selection method

Info

Publication number: WO2014199621A1
Application number: PCT/JP2014/003058
Authority: WO
Inventors: 昌志中田; 佳央植田
Original assignee: 日本電気株式会社
Priority date: 2013-06-10
Filing date: 2014-06-09
Publication date: 2014-12-18
Also published as: JP6090612B2; JP6508395B2; EP3010282B1; JP2018170774A; JP6354875B2; JP2019126089A; US20160142952A1; US10743223B2; JP6669297B2; EP3010282A1; EP3010282A4; JP2017077033A; JPWO2014199621A1

Abstract

[Problem] To provide: a handover control method capable of identifying a target cell in a hand-in phase, even in a network configuration having relay devices connected in multiple stages; a relay device; and a target cell selection method. [Solution] A wireless communications system having a base station control device (14) and a first relay device (1) connected to a communications network, at least one first base station (12) connected under the control of the base station control device, at least a second relay device (2) connected under the control of the first relay device, and at least one second base station (4-6) connected under the control of the second relay device, and wherein: the first relay device obtains cell information for a cell controlled by a second base station under the control of the second relay device; and, the first relay device identifies a target cell for handover by using the cell information, in a hand-in phase in which a wireless station (16) hands over from a wirelessly connected first base station (12) to a second base station (6).

Description

Handover control method, relay device and target cell selection method in wireless communication system

The present invention relates to a handover control technique in a radio communication system, and more particularly to a handover target cell selection method in a relay apparatus.

In 3GPP (3rd Generation Partnership Project), HNB (Home Node B) is defined as a small base station that can be installed in the office or in the user's home, and access to the operator network of the user terminal (UE: User User Equipment) through the HNB. It is possible. Since a wireless area covered by one HNB is a narrow range such as in an office or a user's house, it is also called a small cell, a micro cell, a femto cell, a pico cell, or the like. Hereinafter, for the sake of convenience, “femtocell” is used as including these cells. A large number of such femtocells are generally set in a macrocell that covers a wide area.

In 3GPP, PSC (Primary Scrambling Code) is defined as physical cell identification information of the cell, and each cell can use different PSC to identify the cell, and the logical cell identification information (Cell Identity) of the cell from PSC Is tied to However, the number of physical cell identification information is limited. For example, in UMTS (Universal Mobile Telecommunications System), the maximum number of PSC is 512, and in LTE (Long Term Evolution) system, PCI (Physical Cell Identity) is maximum 504. . For this reason, PSCs are used redundantly for a large number of femtocells set in a macro cell, and Cell Identity cannot be uniquely linked from the PSC. This is the cause of PSC ambiguity. Specifically, in the case of a legacy UE prior to 3GPP Release 9, that is, a UE that does not support a function (SI Acquisition function) for acquiring system information (System Information) of a cell other than a cell that is wirelessly connected, the handover source The RNC (Radio Network Controller) of the macro network cannot uniquely determine the target cell corresponding to the PSC reported by the UE. Non-patent

documents

1 and 2 disclose a method (Disambiguation) for solving such PSC ambiguity (= PSC Confusion).

Hereinafter, the PSC ambiguity solving method in RNC and HNBGW (HNB Gateway) will be described using the system shown in Fig. 1 as an example.

A) PSC ambiguity resolution in RNC According to the supplementary document C.2 (pages 75 to 76) of Non-Patent Document 1, first, as a first step, the UE connected to the HNB of the femtocell is In the process of handing over (handing out) to a macro cell, information necessary for the RNC is stored in a database. Subsequently, as a second step, the target cell (femto cell) is specified by using information in the database when the UE hands in.

Specifically, in the first step, the UE located in the femto cell transmits a measurement report (Measurement Report) to the HNB, and in response, the HNB transmits a handover request message to the RNC via the HNBGW. The RNC stores and learns the information of the handover request message in a database. This database information includes femto cell logical cell identification information (Cell Identity) and its PSC, macro cell Cell Identity under RNC and its PSC, and the time difference between the femto cell and macro cell reference time measured by the UE (Delta Observed) Time Difference: Delta_OTD) is included.

Subsequently, in the second step, when receiving the Measurement Report from the UE located in the macro cell, the RNC acquires the Cell Identity of the femto cell serving as the handover target from the database information, and performs handover to the HNB of the femto cell via the HNBGW. Send a request message. In this handover request message, the Cell identity of the femto cell is set, and this Cell identity is the Cell identity set in the UE History information in the handover request message in the first step handout.

B) PSC ambiguity resolution in HNBGW According to the supplementary material C.3 (pages 76-77) of Non-Patent Document 1, it is basically the same as the method solved by RNC in Chapter C.2, but the database The storage location is HNBGW.

First, in the first step, a handover request message is transmitted from the HNB as described above. When the HNBGW receives the handover request message, it builds database information from the message and forwards the handover request message to the RNC. The database information includes femto cell logical cell identification information (Cell Identity) and its PSC, Cell の Identity of the macro cell under the RNC and its PSC, and delta_OTD information related to the femto cell and its neighboring macro cell. delta_OTD represents the time difference between the reference time of the macro cell and the femto cell measured by the UE.

Subsequently, in the second step, the UE transmits a Measurement Report to the RNC, and the RNC transmits a handover request message including the Measurement Report to the HNBGW. The HNBGW selects the handover target femto cell from the Cell Identities set in the UE History Information of the handover request message and the constructed database information, and transmits the handover request message to the HNB of the femto cell.

However, the above-described PSC ambiguity solving methods A and B are applicable when the HNB registered in the HNBGW is composed of one cell as shown in FIG. As shown in FIG. 2, in a configuration in which HNBGWb is registered in HNBGWa and a plurality of HNBb1 and NBHNBb2 are connected under HNBGWb, a case where a handover target cell cannot be specified may occur as described below.

When the PSC ambiguity solving method A in the RNC is applied to the system shown in FIG. 2, in the first step in which the RNC constructs the database, the Cell Identity set in the UE History Information of the handover request message at the time of handout HNBGWb CellbIdentity or HNBb2 Cell Identity is set.

A. 1) When Cell Identity of HNBGWb is set in UE History Information, HNBGWa can identify Cell Identity of HNBGWb, but HNBGWb cannot identify which HNB under its control is a handover target cell.
A. 2) When the Cell Identity of HNBb2 is set in UE History Information, HNBGWa knows only the Cell Identity of HNBGWb and does not know the HNB Cell Identity under its control. Even if it sees Identity, it does not know which HNB or HNBGWb should transmit a handover request message.

Thus, with the RNC database information constructed by handout, hand-in to the femtocell under the HNBGWb shown in FIG. 2 cannot be realized.

When the PSC ambiguity solving method B in the HNBGW is applied to the system shown in FIG. 2, in the first step of constructing the database, the Cell Identity 設定 set in the UE History Information of the handover request message at the time of handout is set in the HNBGWb Cell Identity or Cell Identity of HNBb2 is set.

B. 1) When Cell Identity of HNBGWb is set in UE History Information, HNBGWa does not know which HNB under HNBGWb is handed out, so it cannot know PSC of HNBb2 cell and transmits from UE The OTD of the cell of HNBb2 cannot be specified from the measured result. For this reason, the delta_OTD regarding the femtocell of HNBb2 and the macro cell under the RNC cannot be calculated.
B. 2) When Cell Identity of HNBb2 is set in UE History Information, HNBGWa has only information of Cell Identity of HNBb2 and does not know PSC of HNBb2. Therefore, the OTD of the cell of HNBb2 cannot be specified from the measured result. As a result, it is impossible to calculate delta_OTD related to the femtocell of HNBb2 and the macro cell under the RNC.

For this reason, the HNBGWa cannot acquire information that can identify the HNBGWb and the HNBb2 from the handover request message received in the second step, even if referring to the database information. That is, with the database information of HNBGWa constructed by handout, hand-in to the femtocell under HNBGWb shown in FIG. 2 cannot be realized.

As described above, the PSC ambiguity solving methods described in

Non-Patent Documents

1 and 2 can be put into practical use only in a configuration in which a base station connected to the HNBGW has one cell as shown in FIG. In a network configuration having a multi-stage configuration of HNBGW-HNB as shown in FIG. 2, there are cases where a target cell in the hand-in phase cannot be specified.

Therefore, an object of the present invention is to provide a handover control method, a relay device, and a target cell selection method that can specify a target cell in the hand-in phase even in a network configuration in which relay devices are connected in multiple stages. It is in.

In the handover control method according to the present invention, a base station control device and a first relay device are connected to a communication network, and at least one first base station is connected under the base station control device. Is a handover control method in a wireless communication system in which at least a second relay device is connected to at least one second base station under the second relay device, wherein the first relay device is the second relay device. In the hand-in phase in which cell information of a cell controlled by a second base station under the control of a relay apparatus is acquired and the radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station, the first relay An apparatus specifies the target cell for the handover using the cell information.
A relay device according to the present invention is a relay device that is connected to a communication network to which a base station control device is connected and has at least a lower level relay device connected thereto, and has at least one first subordinate to the base station control device. Storage means for storing cell information of a cell to which a base station is connected, at least one second base station is connected under the lower relay apparatus, and controlled by the second base station under the lower relay apparatus; Control means for specifying a handover target cell using the cell information in a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station. Features.
In the target cell selection method according to the present invention, a base station control device and a first relay device are connected to a communication network, and at least one first base station is connected under the base station control device. A method of selecting a target cell in the first relay device in a wireless communication system in which at least a second relay device is connected to the subordinate and at least one second base station is connected to the second relay device, the storage means Stores cell information of a cell controlled by a second base station under the control of the second relay device, and the control means performs handover from the first base station to which the radio station is wirelessly connected to the second base station. In the hand-in phase, the handover target cell is selected using the cell information.
In a wireless communication system according to the present invention, a base station control device and a first relay device are connected to a communication network, and at least one first base station is connected under the base station control device, and the subordinates of the first relay device are connected. At least a second relay device, and at least one second base station connected to the second relay device, wherein the first relay device is subordinate to the second relay device. In the hand-in phase in which cell information of a cell controlled by the second base station is acquired and the wireless station performs handover from the first base station to which the second wireless base station is wirelessly connected to the second base station, the first relay device includes The handover target cell is specified using cell information.

According to the present invention, the first relay device acquires the cell information of the second base station under the second relay device, and uses the acquired cell information in the hand-in phase to the cell of the second base station. Thus, it is possible to specify the target cell connected under the second relay device on the target cell side.

FIG. 1 is a configuration diagram showing a system architecture for explaining the background art. FIG. 2 is a configuration diagram showing a system architecture for explaining the problems of the background art. FIG. 3 is a block diagram showing an example of the architecture of a wireless communication system according to an embodiment of the present invention. FIG. 4 is a block diagram showing a schematic configuration of the first relay device in the present embodiment. FIG. 5 is a block diagram showing a schematic configuration of the second relay device in the present embodiment. FIG. 6 is a sequence diagram showing a handover control operation of the wireless communication system according to the present embodiment. FIG. 7 is a schematic diagram showing an example of database storage information in the present embodiment. FIG. 8 is a block diagram showing an example of the architecture of a wireless communication system for explaining an embodiment of the present invention. FIG. 9 is a sequence diagram illustrating a handover target cell selection method according to the first embodiment of the present invention. FIG. 10 is a schematic diagram for explaining the format of the HNB registration request message in the first embodiment. FIG. 11 is a schematic diagram for explaining the format of the HNB configuration update message in the first embodiment. FIG. 12 is a flowchart showing the cell information registration operation in the first embodiment. FIG. 13 is a schematic system configuration diagram showing the sequence of the hand-in phase in the first embodiment. FIG. 14 is a flowchart showing a search and cell characteristic operation using the database in the first embodiment. FIG. 15 is a flowchart showing the filtering operation in FIG. FIG. 16 is a flowchart showing the handout operation in the first embodiment. FIG. 17 is a sequence diagram illustrating a handout phase in the handover target cell selection method according to the second embodiment of the present invention. FIG. 18 is a schematic system configuration diagram showing the sequence of the handout phase in the second embodiment. FIG. 19 is a flowchart showing the cell information registration operation in the second embodiment. FIG. 20 is a flowchart showing cell information registration operation at the time of handout in the second embodiment.

In a network to which an embodiment of the present invention is applied, a base station controller connected to a network connects a plurality of first base stations, and a first relay device connected to the same network is connected to a base station It is assumed that the second relay device is connected, and the second relay device is connected to a plurality of second base stations. In such a multi-stage network, the radio station performs hand-in from the first base station under the control of the base station controller to the second base station under the second relay device as follows. First, the first relay device acquires cell information of a second base station that is under the second relay device. When the wireless station receives a handover request for handing in to the cell of the second base station, the first relay device uses the registered cell information to connect to the subordinate of the second relay device on the target cell side. The second base station that is the selected target cell can be specified. Hereinafter, an embodiment and an example of the present invention will be described in detail.

1. 1. Embodiment 1.1) System Configuration FIG. 3 shows an example of a multistage network configuration to which a wireless communication system according to an embodiment of the present invention is applied. However, in order to avoid complication of explanation, one base station 10 and one relay device (second relay device 2) are connected under the control of one relay device (first relay device 1). And Without being limited thereto, a plurality of base stations and a plurality of relay devices may be connected under the first relay device 1, and no base station is installed under the first relay device 1. Form may be sufficient.

In FIG. 3, the base station 10 controls the cell 11, and the second relay apparatus 2 connects a plurality of base stations (here, three base stations 4-6) under the control of the base station 4-6. 7-9 are controlled respectively.

The first relay device 1 is connected to the base station control device 14 and the core network 15, and the base station 12 connected to the base station control device 14 controls the cell 13. The cell 13 is a cell covering a wide range, and it is assumed that the cell 7-9 and the cell 11 are adjacent to the cell 13. For example, the cell 13 is a macro cell, and the cells 7-9 and 11 are femto cells adjacent to the macro cell 13. The radio station 16 is a mobile station, user terminal, portable terminal, or the like that can move between cells.

In FIG. 3, the cell 7-9 subordinate to the second relay device 2 is treated as one virtual cell 3 constructed by the second relay device 2 when viewed from the base station control device 14. A virtual cell is a cell as one management unit viewed from the base station control device 14 or the first relay device 1, and a plurality of base stations or first relay devices 1 in the cell managed by the base station control device 14. Alternatively, it means that a plurality of cells controlled by the second relay apparatus 2 are virtually regarded as one cell. Therefore, when viewed from the base station controller 14, not only the virtual cell 3 but also a cell 7-9 added with the cell 11 can be handled as one virtual cell.

According to this embodiment, cell information related to the cells 7-9 subordinate to the second relay device 2 is registered in the database of the first relay device 1 by some method. When the radio station 16 wirelessly connected to the base station 12 of the cell 13 hands in from the cell 13 to the cell 9, the first relay device 1 is registered in the database when receiving the handover request from the base station control device 14. By referring to the cell information, it is possible to know that the target cell of the handover is the cell 9 under the second relay device 2 and to transmit a handover request to the base station 6 through the second relay device 2 .

1.2) Configuration of Relay Device As shown in FIG. 4, the first relay device 1 includes a communication unit 101, a lower-level device communication unit 102, a protocol message construction unit 103, a database 104, and a control unit 105.

The first relay device 1 can exchange messages with the base station control device 14 and the core network 15 by the communication unit 101, and can exchange messages with the subordinate base station and the second relay device by the lower-level device communication unit 102.

The protocol message construction unit 103 constructs and analyzes a protocol message exchanged between the base station control device 14, the core network 15, the subordinate base station 10, and the second relay device 2. A specific example of the protocol message will be described in an embodiment described later.

The database 104 has the following information: 1) a registration table that correlates the PSC of the cell and the address of the base station or the second relay device 2 that constructs the cell from the cell identification information (Cell Identity); 2) Store and manage neighboring cell information of relay apparatus 2; 3) virtual cell identification information (Cell Identity) mapped from cell 13 to virtual cell (Cell セル Identity); and 4) delta_OTD table. Among them, in the information 3), mapping information from the cell 13 to the virtual cell (Cell Identity) is manually given by the operator as an O & M system parameter of the first relay device 1. In addition, the virtual cell identification information (Cell Identity) is the base station, the second relay device, or the second relay in which the PSC of the handover target cell in the Measurement Report received from the UE by the base station control device 14 is the subordinate of the first relay device 1. In the case where any cell of a base station under the control of the device is indicated, it is Cell Identity set as a handover destination (Target Cell Identity) in the handover table of the base station control device 14. As will be described later, in base station registration, when the first relay device 1 receives a base station registration request message from a subordinate base station or the second relay device 2 through the lower-level device communication unit 102, information included in the message is stored in a database. 104. Details of the database 104 will be described later (see FIG. 7).

The control unit 105 controls the operation of the first relay device 1 and executes operations such as database information construction, protocol processing, and handover request message routing, as will be described later. The functions equivalent to the protocol message construction unit 103 and the control unit 105 can also be realized by executing a program stored in a memory (not shown) on a computer (processor).

As shown in FIG. 5, the second relay device 2 includes a host device communication unit 201, a base station communication unit 202, a protocol message construction unit 203, a subordinate base station information storage unit 204, and a control unit 205. Protocol messages are exchanged between the relay device, subordinate base stations, and UEs.

The second relay device 2 exchanges messages with the first relay device 1 by the higher-level device communication unit 201, and the base station communication unit 202 receives a measurement report from a subordinate base station and transmits a protocol message.

The protocol message construction unit 203 constructs and analyzes a protocol message exchanged between the first relay device 1 and a subordinate base station. A specific example of the protocol message will be described in an embodiment described later.

The subordinate base station information storage unit 204 stores base station information (cell information) of the base stations 4-6 subordinate to the second relay device 2. The cell information includes cell identification information, PSC, address, neighboring cell information, and the like.

The control unit 205 controls the operation of the second relay device 2 and executes operations such as cell information notification processing and handover request message routing, as will be described later. The functions equivalent to the protocol message construction unit 203 and the control unit 205 can also be realized by executing a program stored in a memory (not shown) on a computer (processor).

1.3) Handover Control As shown in FIG. 6, handover control according to the present embodiment is divided into cell information registration / update operation and handover target cell selection operation after receiving a measurement report from the terminal.

<Register / update cell information>
In FIG. 6, the control unit 205 of the second relay device 2 reads cell information of the subordinate base station 4-6 (cell 7-9) from the subordinate base station information storage unit 204, and the protocol message construction unit 203 reads the cell information. Is transmitted to the first relay device 1 through the higher-level device communication unit 201 (operation S20). The cell information may be notified by any method, but there are a method of using a registration request / update message and a method of using a protocol message in the handout phase as will be described later.

When the control unit 105 of the first relay device 1 receives the cell information notification message through the lower-level device communication unit 102, the control unit 105 extracts cell information from the received message, and subordinates the base station subordinate to the database 104 and the subordinate cell of the second relay device 2. The information regarding is registered in a predetermined table format (operation S21). The control unit 105 can update the registration information in the database 104 every time there is a notification of cell information from the second relay device 2.

<Selection of handover target cell>
In FIG. 6, when the base station controller 14 receives a measurement report (Measurement Report) from the UE located in the cell 13 (operation S22), the base station control device 14 specifies the target cell identification information and the transmission destination from the measurement report, and the handover source A handover request message including information related to cell 13 as a cell and measurement report information is transmitted to first relay apparatus 1 (operation S23).

When the first relay apparatus 1 receives the handover request message by the communication unit 101, the control unit 105 searches the database 104 using cell information such as target cell identification information and source cell identification information included in the handover request message, and performs handover. The second relay device 2 and the target cell 9 to which the request message is to be transferred are specified (operation S24).

When the route to the target cell 9 is specified in this way, the control unit 105 transmits a handover request message to the base station 6 of the target cell 9 through the lower-level device communication unit 102 (operation S25), and from the source cell 13 to the target cell 9 Is executed (operation S26).

1.4) Database Information As shown in FIG. 7, the database 104 provided in the first relay device 1 stores, as an example, a base station registration table, a virtual cell ID table, and a cell information / time difference table. .

The base station registration table is constructed by registering the cell identification information, PSC and address based on the registration request / update message or handover request message received from the base station or relay device under the first relay device 1 It is a table that was made. In the network of the present embodiment shown in FIG. 3, for example, with respect to the base station 10, the cell identity of the cell 11, the PSC and the address of the base station 10 are registered as one record. In addition, with respect to the second relay device 2, the cell identity of the virtual cell, the PSC, and the address of the second relay device 2 are not registered. In addition, for each base station 4-6 under the control of the second relay device 2, the Cell identity of each cell 7-9, the PSC, and the address of the second relay device 2 are registered.

The virtual cell ID table is stored under the control of the first relay device 1 or the second relay device 2 based on the registration request / update message or the handover request message received from the base station or relay device under the first relay device 1. It was constructed by registering the mapping between the neighboring macro cell of a certain base station and virtual cells corresponding to a plurality of cells of the base station under the control of the first relay device 1 or the second relay device 2 as seen from the macro cell. It is a table. One macro cell may be mapped to a plurality of virtual cells, or a plurality of macro cells may be mapped to one same virtual cell. In the network of this embodiment shown in FIG. 3, since one virtual cell 3 exists in the macro cell 13, the mCell_ID of the macro cell 13 is mapped to the vCell_ID of the virtual cell 3.

The cell information / time difference table is obtained by using a registration request / update message or a handover request message received from a base station or relay device under the control of the first relay device 1, the base station registration table, and the virtual cell ID table. Regarding femtocells, information on the femtocell and macrocell (identification information, PSC), delta_OTD (time difference of reference time between macro-femtocell) with macrocell, and list (additional information) of delta_OTD with other cells Is composed of. A specific method for calculating delta_OTD will be described in the embodiment.

1.5) Effect As described above, according to the present embodiment, the cell identification information regarding the cell 7-9 under the control of the second relay device 2, the cell information including the PSC information and the address information, or in addition to these, the OTD Cell information including information, information indicating a relationship with a neighboring cell, and the like is registered in the database of the upper first relay apparatus 1. When the radio station 16 wirelessly connected to the base station 12 of the cell 13 hands in from the cell 13 to the cell 9, the first relay device 1 is registered in the database when receiving the handover request from the base station control device 14. By referring to the cell information, it is possible to know that the target cell of the handover is the cell 9 under the second relay device 2 even if the PSC is used redundantly, and the base station 6 through the second relay device 2 A handover request can be transmitted to

2. Wireless Communication System Hereinafter, as an example, each embodiment of the present invention will be described in detail using the wireless communication system shown in FIG. The wireless communication system shown in FIG. 8 has a network configuration corresponding to the system shown in FIG. 3. Corresponding devices are denoted by the same reference numerals, and detailed description of each device is omitted.

Correspondence between the components in FIG. 8 and FIG. 3 is as follows. GW (gateway) 1 and GW2 in FIG. 8 are the first relay device 1 and second relay device 2 in FIG. 3, HNB (Home NodeB) 4-6 and 10 are the base stations 4-6 and 10, and the base station 12 Corresponds to the NodeB 12, the base station controller 14 corresponds to the RNC (RadioRadNetwork Controller) 14, and the UE 16 corresponds to the radio station 16. The macro cell 13 corresponds to the cell 13, and the cells 7-9 and 11 correspond to the femto cells 7-9 and 11, respectively. As described above, a plurality of HNBs and a plurality of GWs can be connected under the control of GW1, and FIG. 8 only shows one HNB and GW, respectively, in order to avoid the complexity of the drawing. Absent. It is also possible to connect only one or more GWs without being connected to the HNB.

In FIG. 8, the radio base station system generally includes a Node B 12 that is a public radio base station covering a wide range and an RNC 14 that controls a plurality of Node Bs. The NodeB 12 constructs the macro cell 13 as a communication area. The RNC 14 that controls the NodeB 12 is connected to the core network 15 including MSC (Mobile Switching Center), SGSN (Serving GPRS Support Node), etc., and can be connected to the GW 1 as described later.

The HNBs 4-6 and 10 are small radio base stations that generally cover a narrow range in one node. The installation location of the HNB is not only a general home but also a condominium, a commercial building, a shopping mall, a downtown streetlight, and the like, and a wide communication area can be constructed by one or a plurality of HNBs.

GW2 is a gateway device that enables a plurality of HNBs to be directly connected, and relays between an HNB system composed of a plurality of HNB4-6 and GW1. GW2 functions as one HNB similar to HNB10 for GW1. In other words, the cell identification information (Cell９Identity) allocated to GW2 is virtually one cell (virtual cell 3) even though there are cells 7-9 constructed by HNB4-6 under GW2. Is considered.

The UE 16 can perform inter-cell handover while receiving a reference signal (pilot signal) from a neighboring cell. Hereinafter, a handover operation between the macro cell 13 and the femto cell 9 will be described in detail. In the handout phase, the femtocell 9 is a source cell and the macrocell 13 is a target cell. In the handin phase, the macrocell 13 is a source cell and the femtocell 9 is a target cell.

GW1 holds HNB identification information (ID), cell identification information (Cell Identity), and PSC information assigned to HNB one by one. The HNB 10 constructs a single cell 11, and a PSC value different from that of an adjacent cell is set in the cell 11. Similarly, GW 1 holds HNB identification information, cell identification information Cell Identity, and PSC information assigned to GW 2 one by one. However, the PSC allocated to the GW 2 does not have to be the same as the PSC value of the cell 7-9 of the subordinate HNB 4-6, and the GW 2 may not hold the PSC information.

Further, when the HNB or GW2 is registered, the HNB identification information and cell identification information are included in the message received from the subordinate apparatus, and the GW1 determines whether the subordinate apparatus is HNB or GW from the HNB identification information and cell identification information. Is also possible.

The GW 2 can be connected to a plurality of HNBs (4, 5, 6), and holds cell identification information and PSC information allocated to each of the subordinate HNBs. Although the same value may be used for the PSC, neighboring cells are generally set to different PSC values in order for the UE 16 to identify the cell. GW2 can treat

cells

7, 8, and 9 together as if it were one virtual cell 3. When registering with GW1, GW2 registration message (3GPP TS 25.469 V11.1.0 (2012-12) UTRAN 情報 Iuh interface Home Node B (HNB) Application Part (HNBAP) signalling (Release 11))). However, since the PSC is an optional parameter that does not always need to be set, the GW 2 may not set the PSC information of the virtual cell 3 in the registration message of the GW 2.

Further, the RNC 14 can be connected not only to one NodeB 12 but also to a plurality of NodeBs, and the cell 13 constructed by the NodeB 12 is larger than the

cells

7, 8, 9, 11, and may include some or all of them. Is possible. Moreover, although RNC14 is connected with GW1 via the core network 15, it is not limited to this, RNC14 and GW1 may be directly connected.

3. First Embodiment According to the first embodiment of the present invention, the database information of GW1 is constructed using cell information included in the HNB registration request / update message received from GW2.

<Register / update cell information>
In FIG. 9, the control unit 205 of the GW 2 includes a cell including cell identification information of the subordinate HNB 4-6 (cell 7-9), information on the PSC and neighboring cells (PSC and delta_OTD, etc.) from the subordinate base station information storage unit 204. The information is read, an HNB registration message (HNB REGISTER REQUEST) is constructed by the protocol message construction unit 203, and is transmitted to the GW 1 through the higher-level device communication unit 201 (operation S30). The HNB registration message will be described later (see FIG. 10).

When the control unit 105 of the GW1 receives the HNB registration message through the lower-level device communication unit 102, the control unit 105 extracts cell information from the HNB registration message, and registers information on the subordinate cells of the subordinate HNB and the GW2 in the database 104 in a predetermined table format. (Operation S31). The control unit 205 of the GW 2 changes the subordinate base station information storage unit when there is a change in the configuration of the subordinate HNB system (addition or removal of the HNB), Cell Identity, PSC, neighboring macro cell, or Delta_OTD information with the neighboring macro cell. The information of 204 is updated (operation S32), the protocol message construction unit 203 constructs an HNB update message (HNB CONFIGURATION 更新 UPDATE) using the updated cell information, and transmits it to the GW1 through the host device communication unit 201 (operation S33). ). The control unit 105 of the GW 1 updates the registration information in the database 104 every time an HNB update message is received from the GW 2 (Operation S34). The HNB update message will be described later (see FIG. 11).

<Selection of handover target cell>
Subsequently, when the RNC 14 receives a measurement report (Measurement Report) from the UE 16 located in the cell 13 (operation S35), the RNC 14 specifies target cell identification information and a transmission destination from the measurement report, and information on the macro cell 13 that is a source cell. And a handover request message including the measurement report information are transmitted to GW 1 (operation S36).

When the GW 1 receives the handover request message by the communication unit 101, the control unit 105 searches the database 104 using cell information such as target cell identification information and source cell identification information included in the handover request message, and forwards the handover request message. The GW 2 and the femtocell 9 to be specified are specified (operation S37).

When the route to the target cell 9 is specified in this way, the control unit 105 transmits a handover request message to the HNB 6 of the femto cell 9 that is the target cell through the lower apparatus communication unit 102 (operation S38), and from the macro cell 13 to the femto cell 9 Is executed (operation S39).

3.1) HNB registration request / update message When an HNB registration message is used as a message for transmitting cell information from GW2 to GW1, one or more combinations of HNB cell identification information (Cell Identity) and PSC may be set. Is possible. Furthermore, it is possible to include delta_OTD information between each HNB and one or more neighboring cells.

As shown in FIG. 10, information on a plurality of cells under the control of GW 2 is stored in Local Cell Information of the HNB registration message. That is, Local Cell Information includes cell identification information Cell-ID and PSC of each subordinate cell, and Neighbor Information includes adjacent cell information (PSC and delta_OTD) of each subordinate cell. In this embodiment, cell identification information Cell-ID and PSC of a plurality of femtocells 7-9 and PSC and delta_OTD of a macro cell 13 adjacent to Neighbor Information are stored in Local Cell Information. Furthermore, Cell ID may be included in the neighboring cell information of subordinate cells in NeighborbInformation, and in this case, the accuracy of the above-described database search (operation S37 in FIG. 9) is increased. In addition, the macro cell ID can be acquired in the registration of the cell information / time difference table in the above-described operations S31 / S34.

The GW 2 can know the delta_OTD between the subordinate HNB and the macro cell 13 by measuring neighboring cells of the subordinate HNB. In that case, when it deviates more than a predetermined threshold value from delta_OTD notified the first time or last time, you may send as update information. In consideration of the possibility of deviation of several chips due to the drift of the cell reference signal due to the radio wave propagation distance or long-time operation, the value of delta に OTD for determining whether or not they are the same can be widened. For example, if the width for delta_OTD is 1000 and the delta_OTD value is 10000, it is determined that the cells have the same delta_OTD information from 9000 to 11000. In this case, it is desirable that the predetermined threshold value for comparison has a width equal to or less than the width of delta_OTD.

In addition, since a width is determined so that the delta OTD is determined to be the same, a shift occurs in the OTD due to a propagation distance difference due to a different location for handover within the cell, and as a result, a shift also occurs in the delta_OTD information Even if it is, it can determine with the same cell and can raise the probability of specifying a target cell. The same effect can be obtained even if the cell reference signal is slightly shifted from the transmission timing of the cell reference signal due to long-term operation of the cell.

A message other than the HNB registration message can be used as a message for transmitting cell information from GW2 to GW1. For example, as shown in FIG. 11, the Sector Information of the HNB update message includes Sector 、 List of all HNBs under GW2, Sector２List additionally connected to GW2, Sector List to be changed, and Sector List to be deleted. Can also be transmitted. Similarly to the case of the registration message, Sector Information stores cell identification information Cell-ID and PSC, and PSC and delta_OTD of the macro cell 13 adjacent to Neighbor Information.

Hereinafter, the cell information registration operation using the HNB registration message (HNB REGISTER REQUEST) will be described.

3.2) Cell Information Registration Phase In FIG. 12, it is assumed that GW2 first transmits an HNB REGISTER REQUEST message to GW1. As illustrated in FIG. 10, the HNB REGISTER REQUEST message mainly includes the following information:
-HNB ID
-Cell Identity
-PSC
-Macrocell information of neighboring HNBs under HNB or GW2.
Other information is not directly related to the present embodiment and will be omitted.

When the lower device communication unit 102 of the GW 1 receives the HNB REGISTER REQUEST message (operation S301), the control unit 105 performs a normal HNB registration procedure (operation S302).

Subsequently, the protocol message construction unit 103 determines whether the registered node is an HNB having only a single cell or a GW 2 having a plurality of cells (operation S303). For this identification determination, parameters of the HNB REGISTER REQUEST message, for example, the IP Address and port number of the transmission source of the received message can be used. Other than this, it can also be distinguished from, for example, character string information, cell identification information (Cell Identity), or PSC information included in the HNB ID.

If the registered node is an HNB having a single femto cell (Operation S303; NO), the control unit 105 registers the combination of Cell Identity, PSC and Address of the HNB in the base station registration table of the database 104 ( Operation S304).

If the registered node is GW2 that enables a plurality of femtocells (operation S303; YES), the protocol message construction unit 103 determines whether the received HNB | REGISTER | REQUEST message includes Local | Cell | Is determined (operation S305). If Local Cell Information is included (operation S305; YES), control unit 105 registers the combination of HNB Cell Identity, PSC and GW2 Address in the base station registration table of database 104 (operation S306). If delta_OTD information between each HNB and at least one neighboring cell is included, the delta_OTD information may be registered in the cell information / time difference table. When Local Cell Information is not included (operation S305; NO) or when the operation S304 is completed, the operation S306 is not executed.

Subsequently, the control unit 105 determines whether or not a macro cell adjacent to the HNB / GW is set in the received HNB REGISTER REQUEST message (operation S307). When the macro cell is set (operation S307; YES), the control unit 105 stores the macro cell information in the vicinity thereof in addition to the HNB / GW information (operation S308). In this way, the table information illustrated in FIG. 7 can be registered in the database 104.

3.3) Hand-in Phase Next, the operation of the hand-in phase in which the UE 16 performs handover from the macro cell 13 to the femto cell 9 will be described with reference to FIGS. The operations S35 to S38 shown in FIG. 13 correspond to the operations S35 to S38 shown in FIG. 9, respectively.

In Figure 13, UE 16 while NodeB12 wirelessly connected within macrocell 13, a PSC _Cell9 from the pilot signal of the femtocell 9, the PSC _Cell13 from the pilot signal of the macrocell 13, respectively receive. At this time, the UE 16 transmits a Measurement Report message to the RNC 14 based on a measurement result such as the pilot reception power of the femtocell 9 being larger than that of the macrocell 13 (operation S35).

The Measurement Report, contains the Event the Result (event results) Measured the Result (measurement result), the Event the Result is set PSC _Cell9 femtocells 9, the Measured the Result, information on the femtocell 9 (PSC _Cell9 , The time difference OTD _cell9 of the reference time between the UE 16 and the femtocell 9) and the information about the macro cell 13 (PSC _Cell13 , time difference OTD _cell13 of the reference time between the UE 16 and the macro cell 13) are set. The time difference OTD treated here is the SFN (System Frame Number) of the physical channel called the primary CCPCH (Common Control Physical Channel) of the femtocell 9 and the macrocell 13 and the Frame Offset of the UE16 RLC Transparent Mode COUNT-C. Chip Offset. In 3GPP TS25.331 V11.4.0 (2013-1) Radio Resource Control (RRC); Protocol specification (Release 11), the OTD is expressed by three parameters: COUNT-C-SFN high, OFF, and Tm.

When receiving the Measurement Report message, the RNC ₁₄ uses the handover routing table provided _{therein, and} from the PSC _{Cell 9 of} the Event Result, the target cell is a cell under the control of the GW 1 (in this case, any cell included in the virtual cell 3). And a RANAP: Relocation Required (handover request) message is transmitted to the core network 15 (operation S36). In this Relocation Required message,
1) Target ID (target identification information)
2) Target Cell Identity
3) UE History Information (terminal history information)
4) Source RNC to Target RNC Transparent Container
Is set. Here, the identification information of GW1 is set as the Target ID, and the cell identification information (virtual cell ID) under the control of GW1 is set as the Target Cell Identity. Further, the UE History Information includes a set of the cell identity of the cell where the UE 16 is located as the IE Cell Identity and the time the UE 16 stayed in the cell as the IE UE Stayed in Cell. It is set for each. In addition, Measurement Report received from the UE 16 is set in the Source RNC to Target RNC Transparent Container.

The GW 1 receives a RANAP: Relocation Request (handover request) message from the core network 15 (operation S36). RANAP: Relocation Request message
1) Target Cell Identity
2) UE History Information
3) Source RNC to Target RNC Transparent Container
Is set. Here, Cell Identity indicating a cell (virtual cell) under GW1 is set in Target Cell Identity, and Measurement Report received from UE 16 is set in Source RNC to Target RNC Transparent Container.

When GW1 receives the RANAP: Relocation Request message, the control unit 105 compares the received RANAP: Relocation Request message information with the information registered in the database 104, and the Cell of the femtocell 9 that the HNB 6 constructs as HandoverHandTarget Cell. The Identity is specified, and the GW 2 to which the HNB 6 is connected is selected as a message transmission destination (Operation S37).

Subsequently, the control unit 105 sets the Cell Identity of the femtocell 9 as the Target Cell Identity, and transmits a RANAP: Relocation Request message in which the GW2 address is set as the destination address from the lower apparatus communication unit 102 (Operation S38). The control unit 205 of the GW 2 that has received this RANAP: Relocation Request message shows that it is a hand-in procedure from the Target Cell Identity of the message to the femtocell 9 of the HNB 6.

3.4) Selection of handover destination In FIG. 14, when the GW 1 receives the RANAP: Relocation Request message from the core network 15 by the communication unit 101 (operation S310), the control unit 105 determines that the Target Cell Identity included in the received message is It is confirmed whether it is included in the HNB registration table of the database 104 (operation S311). If not included (operation S311; NO), the control unit 105 further confirms whether or not the measurement report is correctly set (operation S312). For example, whether or not two or more OTD (Observed Time Difference) information is set for the cell corresponding to the Target PSC set in Event Result, which is event information indicating the handover destination such as Intra-Frequency Measurement Event 1a, 1c, 1e Check if.

If Measurement Report is correctly set (operation S312; YES), control unit 105 executes filtering using the cell information / time difference table in database 104 according to various information set in the RANAP: Relocation Request message. (Operation S313). This filtering process will be described later.

Subsequently, the control unit 105 checks the number of records remaining after filtering (number of candidates) (operation S314), and if the number of candidates is 1, selects the cell-identity of the femtocell corresponding to the candidate (operation S315). ). If the number of candidates is two or more, the delta_OTD calculated from the OTD information included in the Measured Result of the RANAP: Relocation Request message, and the delta_OTD (other-f) of the additional information of the remaining candidates, that is, the OTD for other cells By comparing the difference with the OTD related to the femtocell, only one candidate that most closely matches is selected, and the Cell Identity of the femtocell is specified (operation S316). Since any delta_OTD information is neighboring cell information excluding the target cell and the macro cell, the femto cell can be identified with a higher probability as the neighboring cell information matches the delta_OTD information. A specific example of a method for calculating delta_OTD from OTD information included in Measured Result will be described later.

Thus, when the cell identity of the femtocell is determined by operations S315 and S316, the control unit 105 sets the determined cell identity to the Target cell identity of the RANAP: Relocation request message, and corresponds to the cell identity from the HNB registration table. The address of the HNB / GW to be acquired is acquired and set as the destination. Thus, the RANAP: RelocationReRequest message can be transmitted to the HNB 6 of the femtocell 9 and the handover to the femtocell 9 can be executed (operation S317).

If Measurement Report is not set correctly (Operation S312; NO) or if the number of candidates is 0 in Operation S314, the control unit 105 determines that handover has failed and transmits RANAP: Relocation Failure to the core network 15. Then, the handover is rejected (operation S318). Further, if the Target Cell Identity included in the received RANAP: Relocation Request message is included in the HNB registration table of the database 104 (operation S311: YES), the Target Cell Identity is already a unique cell in the RNC 14 or the core network 15. It is determined that it has been specified, and a RANAP: Relocation Request message is transmitted to the address of the HNB / GW corresponding to the Cell Identity acquired from the HNB registration table (operation S319).

<Calculation method of delta_OTD>
A specific example of a method for calculating delta_OTD from the Measured Results in the above-described operation S316 is shown below. This calculation method is also used in the filtering process in the above-described operation S313 (see operation S336 in FIG. 15 described later).

OTD is the difference between the SFN of the P-CCPCH, which is the cell reference time, and the RLC-Transparent-Mode-Count-C, which is the UE reference time, and consists of IE-COUNT-C-SFN-high, OFF, and Tm. The OTD information is included in the Measured Result of the Measurement Report transmitted from the UE in a set with the PSC for each cell measured by the UE. The PSC of the macro cell 13 is generally included in the Measured Result of the Measurement Report, the PSC of the femtocell 9 is included in the Event Result of the Measurement Report, and OTD_macro, OTD_femto, and delta OTD (mf) are calculated by the following formulas: Is done.

OTD_macro = (COUNT-C-SFN high (macro) * 256 + OFF (macro)) * 38400 + Tm (macro)
OTD_femto = (COUNT-C-SFN high (femto) * 256 + OFF (femto)) * 38400 + Tm (femto)
delta_OTD (mf) = [(OTD_macro-OTD_femto) + 4096 * 38400] mod (4096 * 38400)

The calculation may be performed as follows based on the definition of 3GPP TS25.215 version 11.0.0 Physical layer-Measurements (FDD) (Release 11).
OTD_macro = OFF (macro) * 38400 + Tm (macro)
OTD_femto = OFF (femto) * 38400 + Tm (femto)
delta_OTD (mf) = [(OTD_macro-OTD_femto) + 256 * 38400] mod (256 * 38400)

<Filtering processing S313>
Hereinafter, filtering processing (operation S313 in FIG. 14) using the cell information / time difference table illustrated in FIG. 7 will be described with reference to FIG. Hereinafter, a filtering process procedure using a femto cell PSC, a macro cell ID, a virtual cell ID, and a set of PSC and delta_OTD as a filtering key will be described. However, the order of application of these filtering keys is arbitrary, and FIG. The processing order shown is an example.

In FIG. 15, processing using the femtocell PSC as a filtering key is as follows. Only candidates that match the PSC of Event Result included in the RANAP: Relocation Request message of the cell information / time difference table are left (operation S330).

The process using the macro cell ID as a filtering key is as follows. It is confirmed whether or not UTRAN Cell Identity is set in the first entry of UE History Information (operation S331). If UTRAN Cell Identity is set in the first entry of UE 動作 History Information (operation S331; YES), the macro cell identification information of the cell information / time difference table is included in the first entry of UE History Information included in the RANAP: Relocation Request message. Only candidates that match the set cell identification information are left (operation S332).

Processing using virtual cell identification information as a filtering key is as follows. Only candidates whose virtual cell identification information in the cell information / time difference table matches the target cell identification information (Target Cell Identity) included in the RANAP: Relocation Request message are left (S333). Subsequently, the control unit 105 determines whether or not at least one candidate remains in the cell information / time difference table (operation S334). If no candidate remains (operation S334; NO), the state before the filtering process of operation S333 is executed is returned (operation S335). If a candidate remains (operation S334; YES), the process proceeds to the next process as it is.

The processing using the combination of PSC and delta_OTD as a filtering key is as follows. First, the control unit 105 calculates delta_OTD from Measured Results of the received RANAP: Relocation Request message (operation S336). The calculation of delta_OTD is as described above. Subsequently, only the candidate whose {macro cell PSC, delta_OTD (m-f)} in the cell information / time difference table matches {PSC, calculated delta_OTD (m-f)} obtained from Measured Results is left (operation S337). As already described, in the comparison of delta_OTD, considering the possibility of deviation by several chips due to the radio wave propagation distance and the drift of the cell reference signal due to long-term operation, the value of delta_OTD for determining whether or not they are the same It can also have a width. For example, when the width for delta_OTD is 1000 and the delta_OTD value is 10000, cells having the same delta_OTD information may be determined when the value of delta_OTD is 9000 to 11000.

3.5) Handout Phase Next, the operation when the UE 16 located in the femtocell 9 hands out to the macrocell 13 will be briefly described. However, as described above, when the Neighbor Information includes a macro cell ID in the HNB registration phase, it is not necessary to acquire cell information in the following handout phase. Even when the macro cell ID is not included, the cell can be specified by the filtering process shown in FIG.

In FIG. 16, when receiving the RANAP: “Relocation” Required message from the lower apparatus (operation S401), the control unit 105 of the GW 1 determines whether or not the transmission source is the GW 2 (operation S402). Whether the transmission source is GW or HNB can be grasped from the transmission source address, SCTP (Stream Control Transmission Protocol) Link information, lower layer information, and the like. If the transmission source is GW2 (operation S402; YES), it is determined whether or not UTRAN Cell Identity is set in the UE History information (operation S403). If it has been set (operation S403; YES), PSC information corresponding to the Cell identity of UE History Information is searched from the HNB registration table (operation S404).

Subsequently, it is determined whether or not the measurement report (Measurement Report) is correctly set in the RANAP: “Relocation” Required message (operation S405). Specifically, it is the same as the determination method described in operation S312 of FIG. If Measurement Report is set correctly (operation S405; YES), the target cell identification information set in the RANAP: Relocation Required message or the macro coverage around the HNB / GW that is the source of the RANAP: Relocation Required message It is determined whether or not the cell identification information of the information is included in the virtual cell ID table (operation S406). If included (operation S406; YES), at least one virtual cell identification information corresponding to the cell identification information of the target cell identification information or the macro coverage information is acquired from the virtual cell ID table (operation S407).

When a list of virtual cell identification information is acquired in operation S407, or when cell identification information of target cell identification information or macro coverage information around the HNB / GW that is the transmission source is not included in the virtual cell ID table (operation S406) NO), the control unit 105 calculates delta_OTD from the measurement report of the received RANAP: Relocation Required message (operation S408). A specific example of the calculation method is as described above.

Thus, the control unit 105 stores the cell identification information and PSC of the HNB, the virtual cell ID list, the cell identification information and PSC of the macro cell, the delta_OTD between the macro cell and the femto cell, and the Measured Results in the cell information / time difference table of the database 104. A PSC of another cell included and a list of delta_OTDs of the other cell and the femto cell are stored (operation S409). Thereafter, the rest of the normal handout procedure is executed (operation S410).

3.6) Effect As described above, according to the first embodiment of the present invention, the GW 2 notifies the host GW 1 of the cell information related to the cell 7-9 subordinate to the GW 2 using the HNB registration / update message. Using this, the GW 1 constructs a database relating to cell information. When the UE 16 wirelessly connected to the Node B 12 of the macro cell 13 hands in from the macro cell 13 to the femto cell 9 under the control of the GW 2, when receiving the handover request from the RNC 14, the GW 1 refers to the cell information registered in the database. Thus, it can be known that the target cell of the handover is the femtocell 9 under the control of GW2, and a handover request can be transmitted to the HNB 6 through the GW2.

More specifically, since the GW 2 transmits the cell identification information and the PSC information of the HNB to the GW 1, the GW 1 can store that the cell identification information of the HNB and the PSC information are information under the GW 2. Therefore, the GW 1 can specify the target cell in the hand-in, can determine the transmission destination of the handover request message, and can maintain the wireless communication connection without disconnection even when the UE 16 moves.

In addition, since the GW1 database holds the HNB / GW address information under the cell identification information as the HNB registration table, the target cell identification information in the handover request message correctly identifies the target cell in the hand-in phase. If it can, the destination address of the handover request message can be uniquely determined from the database without using the cell information / time difference table.

Further, since the database of GW 1 holds virtual cell identification information corresponding to macro cell identification information as a virtual cell ID table, filtering of cell information / time difference table by target cell identification information of a handover request message in the hand-in phase. It is possible to increase the probability of specifying the target cell.

Further, since the message transmitted from GW2 to GW1 includes delta_OTD information between the femtocell and the macrocell, GW1 can construct a cell information / time difference table, and GW1 can identify a target cell in the hand-in phase. It becomes possible.

In addition, the message sent by GW2 to GW1 is updated each time a femtocell is added or removed, or a cell-identity change, a PSC change, a neighboring macrocell change, or a delta_OTD change between a femtocell and a macrocell is detected. Information can be sent. Therefore, the GW 1 can construct the latest cell information / time difference table.

GW2 has a mechanism in which GW2 transmits a message to GW1 only when a predetermined threshold value is exceeded in consideration of changes in delta_OTD between femtocells and macrocells. This eliminates the need for frequent transmission of update messages when the GW 1 constructs the latest cell information / time difference table, which contributes to a reduction in network load.

In addition, when the GW 1 determines the same cell from the information in the cell information / time difference table, since it is determined as the same cell if it is within a certain threshold, there is a slight fluctuation of delta_OTD between the femto cell and the macro cell. Even if it exists, the target cell can be specified.

In addition, management by the GW1 of the HNB's femtocell identification information, the GW2's address information and the cell information / time difference table to which the HNB is connected is facilitated, and before the hand-in phase as described in

Non-Patent Documents

1 and 2. The handout phase becomes unnecessary.

4). Second Embodiment According to a second embodiment of the present invention, the database information of GW1 is constructed using a handover request message when the terminal UE16 hands out from the femtocell 9 to the macrocell 13. Hereinafter, the cell information registration / update operation in the handout phase will be described with reference to FIGS. 17 and 18.

The registration / update operation FIGS. 17 and 18 of 4.1) cell information while UE16 is HNB6 and wireless connection femtocell within 9, PSC the PSC _Cell9 from the pilot signal of the femtocell 9, from the pilot signal of the macrocell 13 _Cell13 is received. Then, based on the measurement result that the pilot reception power of the macro cell 13 is larger than the pilot reception power of the femtocell 9, a measurement report (Measurement Report) is transmitted to the GW 2 through the HNB 6 (Operation S40).

This Measurement Report includes an Event Result (measured result) and a Measured Result (measurement result). The PSC _Cell 13 of the macro cell 13 is set in the Event Result, and information related to the macro cell 13 (PSC _Cell 13, The time difference OTD _cell13 of the reference time between the UE 16 and the macro cell 13 and the information about the femtocell 9 (PSC _Cell9 , the time difference OTD _cell9 of the reference time between the UE16 and the mafemto cell 9) are set. The time difference OTD treated here is the SFN (System Frame Number) of the physical channel called the primary CCPCH (Common Control Physical Channel) of the femtocell 9 and the macrocell 13 and the Frame Offset of the UE16 RLC Transparent Mode COUNT-C. Chip Offset. In 3GPP TS25.331 V11.4.0 (2013-1) Radio Resource Control (RRC); Protocol specification (Release 11), the OTD is expressed by three parameters: COUNT-C-SFN high, OFF and Tm.

Upon receiving the Measurement Report message, the GW 2 receives the RANAP: Relocation Required (handover) as described in 3GPP TS 25.413 V11.2.0 (2012-12) UTRAN Iu interface Radio Access Network Application Part (RANAP) signaling (Release 11). Request) message is constructed and transmitted to GW 1 (operation S41). In this Relocation Required message,
1) Target ID (target identification information)
2) Target Cell Identity
3) UE History Information (terminal history information)
4) Source RNC to Target RNC Transparent Container
Is set. Here, the identification information of the RNC 14 is set as the Target ID, and the cell identification information of the macro cell 13 is set as the Target Cell Identity. Further, in the UE History Information, the combination of the identification information of the femtocell 9 in which the UE 16 is located and the PSC is set as the IE Cell Identity.

When the RANAP: Relocation Requested (handover request) message is received, the GW 1 builds the HNB registration table and the cell information / time difference table of the database 104 from the content of the received RANAP: Relocation Request message (operation S42). Furthermore, the GW 1 transmits a RANAP: Relocation Required message to the core network 15 (Operation S43). The configuration of the RANAP: Relocation Required message in operation S43 is the same as the RANAP: Relocation Required message in operation S41 except for the following points.

That is, the PSC information of the cell before handover (here, PSC _Cell9 ) included in the RANAP: Relocation Required message in operation S41 is deleted, and the UE Cell Information in the RANAP: Relocation Required message in operation S43 includes the IE Cell Identity. Cell identification information of the cell in which UE 16 is located (here, Cell 9) is set in IE UE Stayed in Cell, and the past cell stay time of UE 16 (here, Time _{Cell 9} ) is set by the number of cells in the area. .

When the RNC 14 receives the RANAP: Relocation Request message from the GW 1 through the core network 15, the normal handover process is executed thereafter. Note that the handover request message may be transmitted directly from the GW 1 to the RNS 14 without passing through the core network 15.

<Register cell information>
As shown in FIG. 19, the registration procedure of the cell information in the second embodiment is the same as the procedure of removing the operations S305 and S306 from the registration procedure (operations S301 to S308) in the first embodiment shown in FIG.

That is, in FIG. 19, if the registered HNB is an HNB having a single femto cell (operation S303; NO), the control unit 105 sets the combination of the HNB's Cell Identity, PSC, and Address to the base station of the database 104. Register in the registration table (operation S304). When the registration of operation S304 is completed, or when the registered HNB is GW2 having a plurality of femtocells (operation S303; YES), the control unit 105 macroblocks adjacent to the HNB / GW in the received HNB REGISTER REQUEST message. Is determined (operation S307). The determination as to whether or not Local Cell information is included in the HNB REGISTER REQUEST message (Operation S305) and registration of the HNB registration table (Operation S306) are not executed.

<Register cell information during handout>
As shown in FIG. 20, the handout procedure in the second embodiment differs from the handout procedure (operations S401 to S410) of the first embodiment shown in FIG. 16 only in operation S404.

In FIG. 20, when receiving the RANAP: “Relocation” Required message from the lower apparatus (operation S401), the control unit 105 of the GW 1 determines whether or not the transmission source is the GW 2 (operation S402). Whether the transmission source is GW or HNB can be grasped from the transmission source address, SCTP (Stream Control Transmission Protocol) Link information, lower layer information, and the like. If the transmission source is GW2 (operation S402; YES), it is determined whether or not UTRAN Cell Identity is set in the UE History information (operation S403). If set (operation S403; YES), the HNB cell identification information and the PSC and GW2 address information are stored in the HNB registration table of the database 104 (operation S404a).

4.2) Hand-in phase As described above, the HNB registration table, the virtual cell ID table, and the cell information / time difference table of the database 104 are constructed, and by using this database information, as shown in FIG. The hand-in procedure described in FIG. 13 and FIG. 14 can be executed.

4.3) Effects As described above, according to the second embodiment of the present invention, the following effects can be obtained.
First, using a handover request message notified from GW2 to GW1, cell information related to cell 7-9 under GW2 is notified to higher GW1, and GW1 builds a database related to cell information using this. When the UE 16 wirelessly connected to the Node B 12 of the macro cell 13 hands in from the macro cell 13 to the femto cell 9 under the control of the GW 2, when receiving the handover request from the RNC 14, the GW 1 refers to the cell information registered in the database. Thus, it can be known that the target cell of the handover is the femtocell 9 under the control of GW2, and a handover request can be transmitted to the HNB 6 through the GW2.

More specifically, since the GW 2 transmits the cell identification information and the PSC information of the HNB to the GW 1, the GW 1 can store that the cell identification information of the HNB and the PSC information are information under the GW 2. Therefore, the GW 1 can specify the target cell in the hand-in, can determine the transmission destination of the handover request message, and can be maintained without disconnecting the wireless communication connection even when the UE 16 moves.

In addition, in addition to the HNB cell identification information and PSC information, in addition to the HNB cell identification information and PSC information, the IE Cell Identity and Time UE Stayed In Cell IE in the UE History Information in the RANAP: Relocation Required message transmitted from the GW2 to the GW1 in the handout phase Set IE Cell Identity and Time UE Stayed In Cell IE. Furthermore, only the existing IE Cell Identity and Time UE Stayed In Cell IE are set in IE Cell Identity and Time UE Stayed In Cell IE in the UE History Information in the RANAP: Relocation Required message transmitted from the GW1 to the RNC14. Therefore, it is not necessary to add a new parameter to the handover request message transmitted from the GW 1 to the RNC 14, and the normal handover request message setting at the time of handout can be used in the core network 15 or the RNC 14.

Since GW1 holds the virtual cell ID table corresponding to the identification information of the macro cell in the internal database 104, in the handout phase, the cell information / time difference table corresponds to the macro cell that is the target cell or the neighboring macro cell of HNB / GW2. The virtual cell ID list to be stored can also be stored. Thereby, in the hand-in phase, the cell information / time difference table can be filtered by the target cell identification information of the RANAP Relocation Request message, and the probability of specifying the target cell can be increased.

In the HNB registration procedure of HNB / GW2, GW1 automatically constructs a combination of cell identification information and address information of HNB / GW2 having the cell identification information in internal database 104. Therefore, in the hand-in phase, RANAP Relocation When the target cell identification information of the Request message correctly identifies the target cell, the transmission destination address of the RANAP Relocation Request message can be determined from the database 104.

In the handout phase, GW1 automatically stores in the internal database 104 the combination of the cell identification information of the HNB from the UE History Information of the RANAP: Relocation Required message and the address information of the GW2 that is the source of the RANAP: Relocation に Required message. In the hand-in phase, if the target cell identification information of the RANAP Relocation Request message can correctly identify the target cell, the destination address of the RANAP Relocation Request message can be determined from the database 104. .

Furthermore, since GW1 provides a width for determining the same in the delta_OTD information of the cell information / time difference table, an OTD shift caused by a propagation distance difference between handover points in the cell occurs. As a result, delta_OTD information Even if a deviation occurs, it can be determined that the GW1 is the same cell, and the specific probability of the target cell can be increased. The same effect can be obtained even if the transmission timing of the reference signal of the cell is slightly shifted due to long-term operation of the cell.

5. Other Embodiments As a method for the GW 1 to know the combination of the cell identification information of the HNB and the PSC, a method using an HNB registration / update message as in the first embodiment described above, and a UE History as in the second embodiment. There is a method of using IE Time UE Stayed in Cell of Information, but other methods can also be adopted depending on the network architecture or access method. Other embodiments will be described below.

5.1) Third Example According to the third example of the present invention, one combination of Cell Identity and PSC is set in UE History Information.

In the handout sequence shown in FIG. 18, in the RANAP: Relocation Required message in operation S41, multiple combinations of Cell の Identity and Time UE Stayed in Cell can be set in IE UE History Information. In the second embodiment described above, in addition to the originally set UEＣHistory Information information, the combination of HNB PSC and cell identification information is additionally set in Time に UE Stayed in Cell IE.

On the other hand, it is possible to set only one combination of HNB cell identification information and PSC. In this case, IE 動作 UE History Information is not set in the RANAP Relocation Required message transmitted from the GW 1 to the core network 15 in the operation S43 of FIG.

According to the third embodiment, since the GW 2 transmits the cell identification information and the PSC information of the HNB to the GW 1, the GW 1 can store that the cell identification information and the PSC information of the HNB are information under the GW 2. Therefore, the GW 1 can specify the target cell in the hand-in, can determine the transmission destination of the handover request message, and can be maintained without disconnecting the wireless communication connection even when the UE 16 moves.

Furthermore, in addition to the HNB cell identification information and PSC information, in addition to the HNB cell identification information and PSC information, the IERANCell Identity and Time UE Stayed In Cell IE in the UE History Information in the RANAP: Relocation Required message transmitted from the GW2 to the GW1 in the handout phase Set IE Cell Identity and Time UE Stayed In Cell IE. Furthermore, only the existing IE Cell Identity and Time UE Stayed In Cell IE are set in IE Cell Identity and Time UE Stayed In Cell IE in the UE History Information in the RANAP: Relocation Required message transmitted from the GW1 to the RNC14. Accordingly, it is not necessary to add a new parameter to the handover request message transmitted from the GW 1 to the RNC 14, and the normal handover request message setting at the time of handout can be used in the core network 15 or the RNC 14.

5.2) Fourth Embodiment According to the fourth embodiment of the present invention, only two cells of a source cell and a target cell are set as measurement information cells included in the measured result.

According to the fourth embodiment, in the handout phase, only the PSC and OTD information of the source cell and the PSC and OTD information of the target cell are included in the Measured Result of the Measurement Report of the RANAP Relocation Required message described in operation S41 of FIG. Set. In this case, since IE 既存 UE History Information only needs to set the information of the existing UE History Information, the operation is performed on IE UE History Information of the RANAP Relocation Required message that GW1 transmits to core network 15 in operation S43 of FIG. The same value as that set in S41 can be set.

Also, since the PSC set in the Event Result of the Measurement Report of the RANAP Relocation Required message is the PSC of the target cell, the PSC associated with the first Cell Identity of the UE History Information is the value of the Measurement Report of the RANAP Relocation Required message. It is the other PSC that is not the PSC set in Event Result.

In this way, the mapping between the HNB cell PSC which is the source cell and the cell identification information of the HNB is acquired, stored in the HNB registration table, and used as information for creating the cell information / time difference table. it can.

According to the fourth embodiment of the present invention, since GW2 transmits HNB cell identification information and PSC information to GW1, GW1 confirms that the HNB cell identification information and PSC information are information under GW2. I can remember. Therefore, the GW 1 can specify the target cell in the hand-in, can determine the transmission destination of the handover request message, and can be maintained without disconnecting the wireless communication connection even when the UE 16 moves.

Also, the database of GW1 holds the subordinate HNB / GW address information having cell identification information as an HNB registration table. For this reason, if the target cell identification information of the handover request message is correctly specified in the hand-in phase, the destination address of the handover request message can be uniquely set without using the cell information / time difference table. Can be determined from the database.

GW1 automatically constructs in the internal database 104 a combination of cell identification information and address information of HNB / GW2 having the cell identification information in the HNB / GW2 HNB registration procedure. Therefore, in the hand-in phase, when the target cell identification information of the RANAP Relocation Request message correctly identifies the target cell, the destination address of the RANAP Relocation Request message can be determined from the database 104.

In the handout phase, GW1 automatically stores in the internal database 104 the combination of the cell identification information of the HNB from the UE History Information of the RANAP: Relocation Required message and the address information of the GW2 that is the source of the RANAP: Relocation Required message. To construct. Therefore, in the hand-in phase, when the target cell identification information of the RANAP Relocation Request message correctly identifies the target cell, the destination address of the RANAP Relocation Request message can be determined from the database 104.

5.3) Fifth Embodiment According to the fifth embodiment of the present invention, the relationship between the GW 2 to be accommodated and the plurality of HNBs to be accommodated is that GW1 has one or more cells under GW2 as one cell. If managed, it may have the following form.

a) HNB system in which GW and HNB are configured in multiple stages. It can be used in a corporate GW or the like, and as a configuration, a plurality of GWs may exist in the middle.
b) A radio network system composed of an RNC connected to the GW and a plurality of NodeBs.
c) A relay system consisting of a Donor base station and a Relay base station. The Donor base station may perform wired or wireless connection with one or more Relay base stations, and the Donor base station may also construct a cell.
d) C / U separation base station system. C-Plane control is aggregated in one typical system, and there are multiple U-Plane Radio Points.
The present invention can also be applied to the system forms a) to d) described above.

5.4) Sixth Embodiment Although the first to fifth embodiments described above are based on the WCDMA technology, they can be applied to other wireless systems such as LTE (Long Term Evolution), GSM, and WiFi. It is.

For example, in LTE, HeNBGW and HeNB are one femto base station system, and the second HeNBGW of the in-company network is connected to the first HeNBGW of the operator network, and a plurality of HeNBs are further connected thereunder. Even in such a form, the first HeNBGW manages a combination of physical cell identification information (PCI: Physical Cell Identity) and logical cell identification information (Cell Identity) of cells under the second HeNBGW, and the macro eNB and HeNB It can be applied to Hand-in / out operation using Delta_OTD.

5.5) Seventh Embodiment In the second embodiment described above, Intra Frequency Measurement such as Event 1a or Event 1c is used as the cell measurement of the UE. However, Inter Frequency Measurement or OTDOA measurement can also be used. In the case of the different frequency handover, the HNB cell may exist as a beacon cell that broadcasts only the system information of the HNB cell even at the different frequency. It is also possible to use only the value of Tm as delta_OTD information.

5.6) Eighth Embodiment According to the eighth embodiment of the present invention, a cell information / time difference table is constructed by inter-device communication of GW1, RNC14, and HNB.

In the first to seventh embodiments described above, the cell information / time difference table is constructed from the information set in the message. However, since GW1, RNC14, HNB and GW2 each hold the reference time, the direct device It is possible to recognize timing differences through inter-communication. By adding information on the reference time of each cell to the inter-device communication, the cell information / time difference table can be constructed by the GW1.

5.7) Ninth Embodiment According to the ninth embodiment of the present invention, the cell information / time difference table is constructed as the system parameters of GW1.

In the first to eighth embodiments described above, the cell information / time difference table and the HNB registration table are constructed by the GW 1 itself from the inter-device message transmission / reception and the inter-device synchronization function. For example, the information can be set through an external interface. For example, if there is a test terminal that can be manually input or another node collects information on the second relay device or collects field network information including the second relay device, the test terminal or Information may be sent from another node to the first relay device.

5.8) Tenth Embodiment According to the tenth embodiment of the present invention, cell information / time difference tables are constructed in GW1 and GW2, respectively.

In the first to ninth embodiments described above, the cell information / time difference table is constructed as the database 104 held by the GW 1, but a similar mechanism can be provided in the GW 2.

In the above-described embodiments and examples, the processing of the base station and the relay device described above may be performed by a logic circuit prepared according to the purpose. In addition, a program in which processing contents are described as a procedure is recorded on a recording medium that can be read by the base station or the relay device, and the program recorded on the recording medium is read and executed by the base station or the relay device, respectively. It may be. The recording media that can be read by the base station and the relay device include ROMs that are built in the base station and the relay device, in addition to transferable recording media such as floppy disks (registered trademark), magneto-optical disks, DVDs, and CDs. , Memory such as RAM, HDD, and the like. The programs recorded on the recording medium are read by a CPU (not shown) in the base station or relay apparatus, and the same processing as described above is performed under the control of the CPU. Here, the CPU operates as a computer that executes a program read from a recording medium on which the program is recorded.

6). Additional Notes Part or all of the above-described embodiments may be described as the following additional notes, but are not limited thereto.

(Appendix 1)
A base station control device and a first relay device are connected to a communication network, at least one first base station is connected under the base station control device, and at least a second relay device is connected under the first relay device And a handover control method in a wireless communication system in which at least one second base station is connected under the control of the second relay device,
The first relay device acquires cell information of a cell controlled by a second base station under the second relay device;
In a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station, the first relay device uses the cell information to identify a target cell for the handover.
A handover control method characterized by the above.
(Appendix 2)
The handover control method according to supplementary note 1, wherein the cell information includes logical cell identification information and physical cell identification information for identifying a cell of the subordinate second base station.
(Appendix 3)
The first relay apparatus specifies the target cell using physical cell identification information and the cell information of the target cell included in a handover request message received from the base station control apparatus. 3. The handover control method according to 2.
(Appendix 4)
The cell information further includes physical cell identification information used by a neighboring cell controlled by the second base station, and time difference information of a reference time between the cell and the neighboring cell. The handover control method according to

Supplementary Note

2 or 3,
(Appendix 5)
The first relay device includes physical cell identification information of the target cell included in a handover request message received from the base station control device, time difference information of a reference time between the target cell and the source cell, and the cell The handover control method according to appendix 4, wherein the target cell is specified using information.
(Appendix 6)
The handover control method according to any one of appendix 1-5, wherein the first relay device inputs the cell information from the outside.
(Appendix 7)
Appendix 6 characterized in that the second relay device notifies the first relay device of the cell information using a base station registration message or a base station update message for transmitting information on a subordinate second base station. The handover control method described.
(Appendix 8)
The second relay apparatus notifies the cell information to the first relay apparatus using a handover request message in a handout phase for performing handover from the second base station to the first base station. 6. The handover control method according to 6.
(Appendix 9)
In the handover request message in the handout phase, the physical cell identification information of the source cell of the handover is set in the information element related to the history information of the radio station, and the handover is transmitted from the first relay apparatus to the base station control apparatus 9. The handover control method according to appendix 8, wherein the request message includes normal stay time information set in an information element related to history information of the wireless station.
(Appendix 10)
The first relay apparatus includes logical cell identification information related to a cell of the base station immediately below and the cell of the second base station, address information of the base station directly below, the second base station, and the second relay apparatus; Is stored in the base station registration table
Searching the base station registration table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and specifying the destination address of the target cell and the handover request message;
10. The handover control method according to any one of appendix 1-9, wherein
(Appendix 11)
The first relay device includes logical cell identification information of a cell of the first base station, logical cell identification information of at least one virtual cell including the at least one second base station, and a cell of the first base station. And a cell information table that associates the logical cell identification information of the adjacent second base station cell,
Search the cell information table using the logical cell identification information of the target cell of the handover request message received from the base station controller, and narrow down the target cell candidates.
11. The handover control method according to any one of supplementary notes 1-10, wherein:
(Appendix 12)
The cell information table further includes physical cell identification information used by an adjacent cell of the cell of the second base station, and physical cell identification information used by a cell of the second base station adjacent to the cell of the first base station. And time difference information of a reference time between the cell of the second base station and its neighboring cells,
By searching the cell information table using physical cell identification information of the target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, the candidate of the target cell is further Narrow down,
The handover control method according to Supplementary Note 11, wherein
(Appendix 13)
The cell information table further includes physical cell identification information used by other cells excluding the cell of the second base station and the cell of the first base station, and the cells of the other cell and the second base station. Difference information of the reference time between and
By searching the cell information table using physical cell identification information of the target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, the candidate of the target cell is further Narrow down,
13. The handover control method according to

appendix

11 or 12, wherein
(Appendix 14)
Any one of

Supplementary Notes

4, 5, 12, and 13, wherein the first relay device and the second relay device set a width for determining that the time difference information of the reference time between cells is the same. The handover control method according to claim 1.
(Appendix 15)
15. The handover control method according to any one of supplementary notes 1-14, wherein the first relay device specifies a route to the handover target cell using the cell information.
(Appendix 16)
A relay device connected to a communication network to which a base station control device is connected, and at least a lower level relay device connected thereto, wherein at least one first base station is connected under the base station control device; At least one second base station is connected to the subordinate relay device,
Storage means for storing cell information of a cell controlled by a second base station under the lower relay apparatus;
In a hand-in phase in which a radio station performs a handover from the first base station to which the radio station is wirelessly connected, a control unit that specifies a target cell for the handover using the cell information;
A relay apparatus comprising:
(Appendix 17)
The relay apparatus according to supplementary note 16, wherein the cell information includes logical cell identification information and physical cell identification information for identifying a cell of the subordinate second base station.
(Appendix 18)
The supplementary note 17 is characterized in that the control means specifies the target cell using physical cell identification information of the target cell and the cell information included in a handover request message received from the base station control device. The relay device described.
(Appendix 19)
The cell information further includes physical cell identification information used by a neighboring cell controlled by the second base station, and time difference information of a reference time between the cell and the neighboring cell. The relay device according to Supplementary Note 17 or 18.
(Appendix 20)
The control means includes physical cell identification information of the target cell included in a handover request message received from the base station control device, time difference information of a reference time between the target cell and the source cell, and the cell information. 20. The relay device according to appendix 19, wherein the target cell is specified using.
(Appendix 21)
21. The relay device according to any one of appendix 16-20, wherein the control means inputs the cell information from the outside.
(Appendix 22)
The appendix 21 is characterized in that the control means receives the cell information from the subordinate relay apparatus using a base station registration message or a base station update message that transmits information on a subordinate second base station. Relay device.
(Appendix 23)
The supplementary note 21 is characterized in that the control means receives the cell information from the lower relay apparatus using a handover request message in a handout phase for performing handover from the second base station to the first base station. The relay device described.
(Appendix 24)
In the handover request message of the handout phase, physical cell identification information of the source cell of the handover is set in an information element related to the history information of the radio station, and the control means transmits a handover to the base station control device 24. The relay apparatus according to appendix 23, wherein normal stay time information is set in an information element related to history information of the wireless station in the request message.
(Appendix 25)
The storage means includes logical cell identification information relating to a cell of a base station immediately below the relay device and a cell of the second base station, address information of the base station directly below, the second base station, and the lower relay device; Is stored in the base station registration table
The control means searches the base station registration table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and identifies the destination address of the target cell and the handover request message To
25. The relay device according to any one of supplementary notes 16-24, wherein:
(Appendix 26)
The storage means includes logical cell identification information of the cell of the first base station, logical cell identification information of at least one virtual cell including the at least one second base station, and adjacent to the cell of the first base station. A cell information table that associates the logical cell identification information of the cell of the second base station with
The control means searches the cell information table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and narrows down the target cell candidates.
26. The relay device according to any one of supplementary notes 16-25, wherein:
(Appendix 27)
The cell information table further includes physical cell identification information used by an adjacent cell of the cell of the second base station, and physical cell identification information used by a cell of the second base station adjacent to the cell of the first base station. And time difference information of a reference time between the cell of the second base station and its neighboring cells,
The control means searches the cell information table using physical cell identification information of a target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, thereby Further refine the cell candidates,
27. The relay device according to appendix 26, wherein:
(Appendix 28)
The cell information table further includes physical cell identification information used by other cells excluding the cell of the second base station and the cell of the first base station, and the cells of the other cell and the second base station. Difference information of the reference time between and
The control means searches the cell information table using physical cell identification information of a target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, thereby Further refine the cell candidates,
28. The relay device according to appendix 26 or 27, wherein
(Appendix 29)
29. The relay apparatus according to any one of appendices 19, 20, 27, and 28, wherein the control means sets a width for determining that the time difference information of the reference time between cells is the same.
(Appendix 30)
30. The relay device according to any one of supplementary notes 16-29, wherein the control means specifies a route to the handover target cell using the cell information.
(Appendix 31)
A base station control device and a first relay device are connected to a communication network, at least one first base station is connected under the base station control device, and at least a second relay device is connected under the first relay device A target cell selection method in the first relay device in a wireless communication system in which at least one second base station is connected to the second relay device;
A storage unit stores cell information of a cell controlled by a second base station under the control of the second relay device;
The control means selects a target cell for the handover using the cell information in a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station.
And a target cell selection method.
(Appendix 32)
The target cell selection method according to supplementary note 31, wherein the cell information includes logical cell identification information and physical cell identification information for identifying a cell of the subordinate second base station.
(Appendix 33)
The supplementary note 32 is characterized in that the control means specifies the target cell using physical cell identification information and the cell information of the target cell included in a handover request message received from the base station control device. The target cell selection method described.
(Appendix 34)
The cell information further includes physical cell identification information used by a neighboring cell controlled by the second base station, and time difference information of a reference time between the cell and the neighboring cell. The target cell selection method according to Supplementary Note 32 or 33.
(Appendix 35)
The control means includes physical cell identification information of the target cell included in a handover request message received from the base station control device, time difference information of a reference time between the target cell and the source cell, and the cell information. 35. The target cell selection method according to appendix 34, wherein the target cell is specified by using.
(Appendix 36)
36. The target cell selection method according to any one of supplementary notes 31-35, wherein the control means receives the cell information from the outside.
(Appendix 37)
37. The target cell selection method according to supplementary note 36, wherein the cell information is received from the lower relay apparatus using a base station registration message or a base station update message for transmitting information related to a subordinate second base station. .
(Appendix 38)
364. The target cell selection according to appendix 364, wherein the cell information is received from the lower level relay apparatus using a handover request message in a handout phase for performing handover from the second base station to the first base station. Method.
(Appendix 39)
In the handover request message of the handout phase, physical cell identification information of the source cell of the handover is set in an information element related to the history information of the radio station, and the control means transmits a handover to the base station control device 39. The target cell selection method according to supplementary note 38, wherein normal stay time information is set in an information element related to history information of the wireless station in the request message.
(Appendix 40)
The storage means includes logical cell identification information related to the cell of the base station immediately below the relay apparatus and the cell of the second base station, and address information of the base station directly below, the second base station, and the second relay apparatus And a base station registration table that associates
The control means searches the base station registration table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and identifies the destination address of the target cell and the handover request message To
40. The target cell selection method according to any one of supplementary notes 31-39, wherein:
(Appendix 41)
The storage means includes logical cell identification information of the cell of the first base station, logical cell identification information of at least one virtual cell including the at least one second base station, and adjacent to the cell of the first base station. A cell information table that associates the logical cell identification information of the cell of the second base station with
The control means searches the cell information table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and narrows down the target cell candidates.
41. The target cell selection method according to any one of supplementary notes 31-40, wherein:
(Appendix 42)
The cell information table further includes physical cell identification information used by an adjacent cell of the cell of the second base station, and physical cell identification information used by a cell of the second base station adjacent to the cell of the first base station. And time difference information of a reference time between the cell of the second base station and its neighboring cells,
The control means searches the cell information table using physical cell identification information of a target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, thereby Further refine the cell candidates,
42. The target cell selection method according to appendix 41, wherein:
(Appendix 43)
The cell information table further includes physical cell identification information used by other cells excluding the cell of the second base station and the cell of the first base station, and the cells of the other cell and the second base station. Difference information of the reference time between and
The control means searches the cell information table using physical cell identification information of a target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, thereby Further refine the cell candidates,
43. The target cell selection method according to appendix 41 or 42, wherein
(Appendix 44)
44. The target cell selection method according to any one of appendices 34, 35, 42 and 43, wherein the control means sets a width for determining that the time difference information of the reference time between cells is the same.
(Appendix 45)
45. The relay device according to any one of appendices 31 to 44, wherein the control means specifies a route to the handover target cell using the cell information.
(Appendix 46)
A base station control device and a first relay device are connected to a communication network, at least one first base station is connected under the base station control device, and at least a second relay device is connected under the first relay device A wireless communication system in which at least one second base station is connected under the second relay device,
The first relay device acquires cell information of a cell controlled by a second base station under the second relay device;
In a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station, the first relay device uses the cell information to identify a target cell for the handover.
A wireless communication system.

The present invention is applicable to handover control in a mobile communication system having a cell configuration.

1 First repeater (GW)
2 Second relay device (GW)
3 Virtual cell 4-6 Base station (HNB)
7-9 cell (femtocell)
10 Base station (HNB)
11 cells (femtocell)
12 Base station (NodeB)
13 cells (macro cell)
14 Base station controller (RNC)
15 Core network 101 Communication unit 102 Lower device communication unit 103 Protocol message construction unit 104 Database 105 Control unit 201 Upper device communication unit 202 Base station communication unit 203 Protocol message construction unit 204 Subordinate base station information storage unit 205 Control unit

Claims

A base station control device and a first relay device are connected to a communication network, at least one first base station is connected under the base station control device, and at least a second relay device is connected under the first relay device And a handover control method in a wireless communication system in which at least one second base station is connected under the control of the second relay device,
The first relay device acquires cell information of a cell controlled by a second base station under the second relay device;
In a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station, the first relay device uses the cell information to identify a target cell for the handover.
A handover control method characterized by the above.
The handover control method according to claim 1, wherein the cell information includes logical cell identification information and physical cell identification information for identifying a cell of the subordinate second base station.
The first relay apparatus specifies the target cell using physical cell identification information and the cell information of the target cell included in a handover request message received from the base station control apparatus. Item 3. The handover control method according to Item 2.
The cell information further includes physical cell identification information used by a neighboring cell controlled by the second base station, and time difference information of a reference time between the cell and the neighboring cell. The handover control method according to claim 2 or 3.
The first relay device includes physical cell identification information of the target cell included in a handover request message received from the base station control device, time difference information of a reference time between the target cell and the source cell, and the cell 5. The handover control method according to claim 4, wherein the target cell is specified using information.
The handover control method according to any one of claims 1 to 5, wherein the first relay device inputs the cell information from the outside.
The said 2nd relay apparatus notifies the said cell information to the said 1st relay apparatus using the base station registration message which transmits the information regarding the subordinate 2nd base station, or a base station update message. The handover control method according to claim 1.
The second relay apparatus notifies the first relay apparatus of the cell information using a handover request message in a handout phase for performing handover from the second base station to the first base station. Item 7. The handover control method according to Item 6.
In the handover request message in the handout phase, the physical cell identification information of the source cell of the handover is set in the information element related to the history information of the radio station, and the handover is transmitted from the first relay apparatus to the base station control apparatus 9. The handover control method according to claim 8, wherein in the request message, normal stay time information is set in an information element related to history information of the wireless station.
The first relay apparatus includes logical cell identification information related to a cell of the base station immediately below and the cell of the second base station, address information of the base station directly below, the second base station, and the second relay apparatus; Is stored in the base station registration table
Searching the base station registration table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and specifying the destination address of the target cell and the handover request message;
10. The handover control method according to any one of claims 1 to 9, wherein
The first relay device includes logical cell identification information of a cell of the first base station, logical cell identification information of at least one virtual cell including the at least one second base station, and a cell of the first base station. And a cell information table that associates the logical cell identification information of the adjacent second base station cell,
Search the cell information table using the logical cell identification information of the target cell of the handover request message received from the base station controller, and narrow down the target cell candidates.
The handover control method according to any one of claims 1 to 10, wherein:
The cell information table further includes physical cell identification information used by an adjacent cell of the cell of the second base station, and physical cell identification information used by a cell of the second base station adjacent to the cell of the first base station. And time difference information of a reference time between the cell of the second base station and its neighboring cells,
By searching the cell information table using physical cell identification information of the target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, the candidate of the target cell is further Narrow down,
The handover control method according to claim 11, wherein:
The cell information table further includes physical cell identification information used by other cells excluding the cell of the second base station and the cell of the first base station, and the cells of the other cell and the second base station. Difference information of the reference time between and
By searching the cell information table using physical cell identification information of the target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, the candidate of the target cell is further Narrow down,
The handover control method according to claim 11 or 12, wherein the method is a handover control method.
The width for determining that the time difference information of the reference time between the cells is the same between the first relay device and the second relay device is set. The handover control method according to item.
15. The handover control method according to claim 1, wherein the first relay device specifies a route to the handover target cell using the cell information.
A relay device connected to a communication network to which a base station control device is connected, and at least a lower level relay device connected thereto, wherein at least one first base station is connected under the base station control device; At least one second base station is connected to the subordinate relay device,
Storage means for storing cell information of a cell controlled by a second base station under the lower relay apparatus;
In a hand-in phase in which a radio station performs a handover from the first base station to which the radio station is wirelessly connected, a control unit that specifies a target cell for the handover using the cell information;
A relay apparatus comprising:
The relay apparatus according to claim 16, wherein the cell information includes logical cell identification information and physical cell identification information for identifying a cell of the subordinate second base station.
The said control means specifies the said target cell using the physical cell identification information of the said target cell contained in the handover request message received from the said base station control apparatus, and the said cell information. The relay device described in 1.
The cell information further includes physical cell identification information used by a neighboring cell controlled by the second base station, and time difference information of a reference time between the cell and the neighboring cell. The relay device according to claim 17 or 18.
The control means includes physical cell identification information of the target cell included in a handover request message received from the base station control device, time difference information of a reference time between the target cell and the source cell, and the cell information. The relay device according to claim 19, wherein the target cell is specified using a message.
21. The relay apparatus according to claim 16, wherein the control means inputs the cell information from the outside.
The said control means receives the said cell information using the base station registration message or the base station update message which transmits the information regarding the subordinate 2nd base station from the said low-order relay apparatus, It is characterized by the above-mentioned. The relay device described.
The control means receives the cell information from the lower relay apparatus using a hand-out phase handover request message for handing over from the second base station to the first base station. The relay device described in 1.
In the handover request message in the handout phase, physical cell identification information of the source cell of the handover is set in an information element related to the history information of the radio station, and the control means transmits the handover to the base station control device The relay apparatus according to claim 23, wherein normal stay time information is set in an information element related to history information of the wireless station in the request message.
The storage means includes logical cell identification information relating to a cell of a base station immediately below the relay device and a cell of the second base station, address information of the base station directly below, the second base station, and the lower relay device; Is stored in the base station registration table
The control means searches the base station registration table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and identifies the destination address of the target cell and the handover request message To
The relay device according to any one of claims 16 to 24, wherein:
The storage means includes logical cell identification information of the cell of the first base station, logical cell identification information of at least one virtual cell including the at least one second base station, and adjacent to the cell of the first base station. A cell information table that associates the logical cell identification information of the cell of the second base station with
The control means searches the cell information table using the logical cell identification information of the target cell of the handover request message received from the base station control device, and narrows down the target cell candidates.
The relay device according to any one of claims 16 to 25, wherein:
The cell information table further includes physical cell identification information used by an adjacent cell of the cell of the second base station, and physical cell identification information used by a cell of the second base station adjacent to the cell of the first base station. And time difference information of a reference time between the cell of the second base station and its neighboring cells,
The control means searches the cell information table using physical cell identification information of a target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, thereby Further refine the cell candidates,
27. The relay apparatus according to claim 26.
The cell information table further includes physical cell identification information used by other cells excluding the cell of the second base station and the cell of the first base station, and the cells of the other cell and the second base station. Difference information of the reference time between and
The control means searches the cell information table using physical cell identification information of a target cell of the handover request message and time difference information of a reference time between the target cell and the source cell, thereby Further refine the cell candidates,
28. The relay apparatus according to claim 26 or 27.
The relay device according to any one of claims 19, 20, 27 and 28, wherein the control means sets a width for determining that the time difference information of the reference time between cells is the same.
The relay device according to any one of claims 16 to 29, wherein the control means specifies a route to the target cell for the handover using the cell information.
A base station control device and a first relay device are connected to a communication network, at least one first base station is connected under the base station control device, and at least a second relay device is connected under the first relay device A target cell selection method in the first relay device in a wireless communication system in which at least one second base station is connected to the second relay device;
A storage unit stores cell information of a cell controlled by a second base station under the control of the second relay device;
The control means selects a target cell for the handover using the cell information in a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station.
And a target cell selection method.
A base station control device and a first relay device are connected to a communication network, at least one first base station is connected under the base station control device, and at least a second relay device is connected under the first relay device A wireless communication system in which at least one second base station is connected under the second relay device,
The first relay device acquires cell information of a cell controlled by a second base station under the second relay device;
In a hand-in phase in which a radio station performs handover from the first base station to which the radio station is wirelessly connected to the second base station, the first relay device uses the cell information to identify a target cell for the handover.
A wireless communication system.